Black Bullet, White Justice
by Epsilon Zeta
Summary: After mankind lost the war to the Gastrea, they isolated themselves in Varanium Monoliths for safety. But that does not stop them from believing that they can reach the blue sky...


Gastrea – a mysterious virus that suddenly appeared before mankind. This virus enters the human body through bodily fluids causing infection. It alters the victim's DNA and form. Because of its contagiousness, it immediately spread throughout the entire world. After its breakout, Gastrea quickly took mankind's spot at the top of the food chain.

**Disclaimer: I own nothing about Black Bullet or Kamen Rider. **

**First Shot: Symphony Rerelease**

During the ten years after mankind lost the war to Gastrea in 2021, Monoliths were created from Varanium, a metal that prevents Gastrea from entering human settlements. However, some Gastrea are able to bypass the barriers. As a result, Civil Security Agencies were created and organized two-man teams to fight the Gastrea: one being the Promoter, tasked with analyzing battle situations. The other being the Initiator, young girls who possess the Gastrea Virus but are able to maintain their human form and gain superhuman abilities as a result.

In order to reduce the death rate of law enforcement officers, a law came into effect, stating that in any incident in which Gastrea are involved; they cannot enter the premise without a Promoter and Initiator pair.

So the chief from the homicide department found himself a bit surprised when only the Promoter came to the 'Grand Tanaka' apartment complex. What was more surprising is the fact that the Promoter only appeared to be a high school student clad in the uniform of Magata High School. "Can I see your license?"

The boy merely handed over a card, identifying him as Satomi Rentaro of the Tendo Civil Security Agency.

"Tendo Civil Security Company, huh? Never heard of it." The older man gave the card back to Rentaro.

"We aren't very well-known. Hey, sorry for rushing, but why don't we get down to business already, Inspector…?"

"Tadashima," introduced the man in a rough tone before leading the way to the apartment elevator. "The guy from room 102 called us while screaming, and said that blood was leaking from the roof. After putting together all the information we have, we're certain that it's a Gastrea. Now that you're here, we can finally enter the premises and investigate properly."

"The law is there for safety reasons and to reduce the number of victims," countered Rentaro.

The older man grunted once. "Hmph. By the way, where's your Initiator partner?"

"I-uh, I don't think I will need her help at this time."

* * *

"_Rentaro, that idiot! Regardless of the urgency, how could he throw me, his cute fiancée, off the bicycle and leave?! You agree that's stupid too, right?!"_

'Man, he's going to be in for it…' With a heavy sigh, the young man on the receiving end of Aihara Enju's phone call tried to get the conversation back on track. "Yeah, I do think that's a bit silly. Now did you have something actually important to tell me or are you just venting?"

"_You're the one who built his belt! You can track him down, right?!"_

"Honestly, you should have just remembered the job location in the first place."

"_All he told me was we had a job and to get ready!"_

The young man shifted in his seat and turned to his laptop to resume the work he had been doing earlier before getting the call from Enju. "Then why don't you try calling Kisara-san? She should have the job location on her."

"_If I call her, then she'll call Rentaro to find out what's going on! Then one talk leads to another which then leads to dates and then to marriage and then to babies!"_

He really wondered where that leap in logic came from. Maybe all Cursed Children were like that. "Enju, you really ought to not let yourself get worked up like-"

"_Someone's coming."_ She paused for a moment. _"I see it. I have to go."_

Ah, work was calling. "Take care then." As soon as he hung up the phone, he dialled another number on it and waited for the recipient to answer. "You're in position?"

"_Yes, yes! The festival's going to begin soon!"_

"Good." He had to see how the belt did. It had been a year's worth of hard work to translate the Rider system data he had on him into something that could actually be built with this world's resources. He really had to thank Sumire for all of her help. Her research was in an entirely different area but she had still given him direction on how to build the armour and weapons.

With luck, the first test run will go well against the Gastrea they were hunting. Of course, it depended on the level of the Gastrea but it was likely a mere Stage I. Just to be safe, he decided to head over to the job site on his motorcycle. After all, if the system didn't work as planned and Enju got somehow incapacitated, he would need to save the day.

* * *

While Enju placed her phone away, her eyes were locked on to the man who looked like a walking corpse. A large wound, as if he was torn up, spread up to the tip of his shoulder and his throat; fresh blood was still gushing from it. A big puddle of blood had formed on the asphalt road where he was standing.

"Young lady, can you please give me some directions?"

She just stared at him for a while before the look in her eyes changed. Her face was now one of pity. "Mister, do you know what happened to you?"

"What do you mean?"

"There's nothing I can do about it. No one can. Uhm... Well, do you have any last words? To your friends, your family or maybe someone else?"

Her behaviour was extremely puzzling to the man. "...What on earth are you talking about?"

"Well, that's it and there's nothing else I can say to you, even if I wanted to. But, Rentaro told me, 'It's your duty to convey the message to the aforementioned people', so I promise to pass them your words."

"I still don't follow, young lady."

She sighed softly. "Seems like you haven't noticed it yet. In that case, it'd be better to take a look at your body. But you should take it slow, so that you won't panic. If you do as I say, then you'll understand what I'm talking about."

He finally looked at himself and gasped. "W-what is this? Why haven't I noticed this before? Why haven't I felt any pain? How did this even happen to me? I remember…"

Enju stayed silent so he could get his last words out.

"I... remember. Yes, I became poor and then... I got lucky and got a job."

The job would have been at a company that specialized in cleaning solar cell modules. He figured that it would be tough, but he had a guaranteed and modest salary. And once he got back to his feet, he could return to his wife and baby girl.

"I wanted to call her and let her know the good news. I went out to the balcony…"

This was supposed to be a starting point to mending their strained relationship. But while he was waiting for the recipient to answer the call, he suddenly looked upwards and saw it.

That creature that was clinging to the wall on the fourth floor of the apartment. The creature that had red eyes and fell on him.

"...I was about to be killed by that Gastrea, so I ran away like hell and came here."

"That Gastrea left its body fluids in you," remarked Enju in a simple tone.

The man looked at two fang marks at the tip of his shoulder.

"So that explains it." He remembered the TV broadcasts that he had seen numerous times during the war. Laboratory rats that were injected with the Gastrea virus became strangely-shaped a few minutes later and screamed like newborn babies, leaving the audience speechless.

In a flash, he felt his calves became itchy. His body temperature grew and he felt a pressure as if his insides were swelling. It would not be long until he was no longer human.

"Young lady, my name is Sumiaki Okajima… and please tell my wife and daughter that I'm sorry for what I've done."

Those were his last words as his body temperature exceeded the critical point and his human form ripped itself apart. Out came eight long legs covered with hair with four pairs of vermillion eyes appearing in place of his head. His abdomen swelled like a ball, two wet glittering fangs protruded from the corners of his mouth.

Enju immediately recognized the enemy type she was facing. "Gastrea confirmed— model: spider, Stage I."

The monster immediately spotted her and spat out some webbing which trapped one of Enju's legs. "Eh?! Ewww! This is all sticky!"

With a single screech, the spider then slapped her away, sending her crashing through a wooden fence.

"Enju, are you all right?!"

As she regained her senses, she saw that Rentaro had arrived on the scene. As soon as she got up, she ran over to him before kicking him in the groin.

"AAARRRGGHHH!"

The boy fell to his knees holding his groin with both hands and touched the ground with his forehead while his Initiator partner glared down at him. "How dare you show up in front of me as if nothing happened after you threw me off the bicycle?!"

"I take it you're mad?"

"Of course I am!" shouted the small girl.

"It really couldn't be helped. We had to move fast to take this job and if I didn't get here in time, Kisara would've kicked my ass, you know?" Work was difficult to find at times and as finances were tight at the Tendo Civil Security Agency, every little job helped.

"Since you abandoned me, I'm gonna kick your ass too."

"So what am I supposed to do then?!" shouted the high school student in frustration.

"Just bend over, raise your butt and accept your punishment like a man. Then you'll be kicked by both of us. Perhaps, you can even choose the way we'll kick you," chirped Enju without missing a beat.

"You're being silly. There must be another way." He was certainly not going to indulge her in this request if he could help it! The well-being of his ass was on the line!

The next moment, a gun-shot roared and broke through their conversation. Tadashima finally arrived, holding a revolver that was giving off smoke.

"Hey, you two! Are you trying to kill the enemy by making it laugh at you?! Do your job, Civil Security Agents!"

The shots fired by the older man didn't have any effect on the Gastrea as it instantly regenerated and had its sights focused on them. "Inspector, normal bullets won't work on them! It'll just agitate it more!" With a single motion, Rentaro took out his own gun before tossing it to Tadashima. "Take this! It has Varanium bullets!"

"Y-you're lending this to me?! But what about you?"

"I have another weapon on me! Just try not to waste your shots!"

The spider Gastrea began to approach but Tadashima fired at it with his new weapon. Thanks to the Black Bullets, the regenerative ability of the Gastrea did not kick in. "It's working!"

'This is it.' Rentaro normally wasn't one to feel nerves but if this system really worked… if the hard work of the young man he met a year ago paid off, then this could change the status quo of the world and perhaps allow humanity to take the fight to the Gastrea.

Taking a deep breath to calm himself down, he loosened his blazer, revealing a strange looking belt on his waist with some sort of technological component in the buckle. He then took out a futuristic looking knuckle and pressed his open palm against it to activate it.

**R-E-A-D-Y!**

It let out a loud whirling sound, indicating it is ready to be used. He lined up his Knuckle perpendicular to the left and drew a straight line to the right with a serious expression.

"Henshin!"

Rentaro then placed it onto his belt, activating it.

**F-I-S-T O-N!**

A gold image of what appeared to be a cross appeared on the Knuckle before it started spinning and appeared in front of him. A mirage of the armor appeared right in front of the figure before it slammed onto him, donning him in her armor before the visor opened up, allowing some heat to vent. On his black bodysuit, he had white pads with blue lines on his side thighs, back, arms and the back of his pelvis. He had silver plated armor on his chest, white shoulder pads with golden highlights on it and finally, on his white helmet, there were golden highlights that revealed the red eyes.

"Gastrea… return the life you took to God!"

The inspector was flabbergasted to see the boy don some sort of strange and powerful looking armour. "W-what is that?"

Without wasting a moment, the newly armoured warrior took out a sword with a red blade and white handle before leaping towards the spider Gastrea and cutting off a limb. "IXA Calibur, Calibur Mode test completed. No outstanding defects."

As soon as he recovered on his feet, the weapon switched modes before blasting an array of shots at the Gastrea, forcing it back. "Gun Mode test completed. No outstanding defects."

With those tests done, Rentaro placed the weapon away before grabbing a whistle from the right side of his belt and placing it into the left portion of his buckle. Then he took a hold of the right portion of the buckle, clicked it once and had it detached.

**I-X-A K-N-U-C-K-L-E R-I-S-E U-P! **

"Tendo Martial Arts First Style, Number Three! Rokuro Kabuto!" Armed with the knuckle, Rentaro spun forward and plowed his fist right through the large abdomen of the Gastrea. The attack had been strong enough for him to rip right through and land on the other side, sending pieces of flesh and purple Gastrea blood everywhere. "IXA Knuckle test completed. All functions working optimally."

"He… just ripped it apart? With his own fists…?" The inspector was no stranger to the power of Cursed Children but to an ordinary boy with that power was an entirely different story.

With the battle over, Rentaro deactivated the armour and caught a flying Enju. "Rentaro, that was awesome! You were like a Knight!"

"Not really." Well, if Enju's mood had improved, maybe she would forget the whole promise to kick his ass earlier.

"And a Knight definitely deserves a kiss from the Princess…!" She puckered up her lips and began moving towards his face.

"Who's a princess here?!" Luckily for Rentaro, the sound of a motorcycle interrupted any further attempts by Enju for a kiss. He could also spot an orange cartoonish looking bat flying beside the motorcycle rider.

Eventually, the vehicle came to a complete stop right in front of the Civil Security Agents and allowed for the inspector to get a good look at the rider once that man took off his helmet. He appeared quite weird with that crazy hair, yellow glasses, orange shirt, black shorts and a green scarf wrapped around his neck. The orange bat came to a halt, resting on the rider's shoulder. "How did everything work out, Rentaro?"

"All systems worked pretty well. It's all thanks to you, Masao."

The son of Kamen Rider Kiva smiled at that. "That's good to hear."

April 28, 2031 would be known in history as the day that Kamen Rider Ixa was reborn into the world to fight against mankind's enemies. With New Kiva fighting beside him, how will the war against the Gastrea unfold now?

**TO BE CONTINUED…**

**Well, finally got the debut chapter of this latest idea off my chest. Like my other non-Bujin Gaim stories, this will be low priority and only worked on when I'm in the mood for it. If this gets lots of reviews, I might consider shifting priorities.**


End file.
